1. Field of the Invention
The invention relates to shuttleless looms wherein weft yarn is drawn from a stationary source and is inserted into sheds of warp threads by opposed carrier members that are attached to the free end of flexible tapes which are alternately wrapped about and extended from oscillating tape wheels located at each side of the loom. The timed sequence with the weaving cycle the weft yarn is acted upon by a presenting member which locates the weft in a position for reception by a so-called inserting carrier which carries said weft into the shed and presents it to a so-called extending carrier the draws the weft through the remainder of the shed to complete a single pick.
In particular the invention pertains to an improved weft yarn tensioning device of the friction plate type whereby the resistance the plates apply to the weft yarn being drawn therebetween can be quickly and easily varied to meet the tensioning requirements of any particular count of weft.
2. Description of the Prior Art
Shuttleless looms to which the present invention is applicable can be of the type in which weft is supplied from one or more sources or which may employ either the Gabler or Dewas system of weft insertion. In such looms, a weft presenting member is actuated in timed sequence with the weaving cycle so as to locate said weft in a position where it will be received into and taken by the inserting carrier into a shed for presentation to the weft extending carrier.
Weft yarn tensioning devices of the spring biased friction plate type are well known to those conversant in the weaving art, and for a detailed showing and description of this type of device, attention is directed to U.S. Pat Nos. 3,280,853 and 3,561,498.
Although these weft yarn tensioning devices have satisfactorily performed their intended function for many years, they have been considered quite troublesome when attempting to establish a uniform tension on a plurality of looms using the same type of weft. Additionally, it has been considered particularly troublesome and time consuming when attempting to reposition the friction plates so as to vary the tension being applied to the weft passing therebetween or to re-locate said friction plates to satisfactorily accommodate a change in weft yarn to one of a different count.
The problems described above of establishing uniform weft tension on several looms and of selectively varying the tension being applied to the weft yarn can be attributed to the fact that the friction plates are carried by post elements individual thereto that are independently mounted in spaced relation on a common support bracket. To reposition the friction plates so that they engage one another with greater or less biasing force requires independent adjustment of each of the post elements. The post elements must first be loosened and than slightly rotated in one direction or the other, depending on the amount of biasing force desired, and then retightened. It is quite obvious that with this means of varying and controlling the tension of weft yarn it would be very difficult to obtain a uniform tension on a plurality of looms utilizing the same weft and necessitates an excessive amount of loom down time to vary and obtain the most desirable amount of tension for a particular count of weft. The weft control device of the present invention has overcome the problems described above by providing a control means for said device which enables the post elements for each friction plate to be simultaneously rotated to anyone of a plurality of pre-determined positions which is effective in a minimum amount of time of increasing or decreasing the amount of biasing force produced by said friction plates as desired.